S.C. Code Ann. § 9-1-1510

(A) A Class One or Class Two member may retire upon written application to the system setting forth at what time, no more than ninety days before nor more than six months after the execution and filing of the application, the member desires to be retired, if the member at the time specified for the member's service retirement has: (1) five or more years of earned service; (2) attained the age of sixty years or has twenty-eight or more years of creditable service; and (3) separated from service. (B) A Class Three member may retire upon written application to the system setting forth at what time, no more than ninety days before nor more than six months after the execution and filing of the application, the member desires to be retired, if the member at the time specified for the member's service retirement has: (1) eight or more years of earned service; (2) attained the age of sixty years or satisfied the rule of ninety requirement; and (3) separated from service. (C) A member who is an elected official whose annual compensation is less than the earnings limitation pursuant to Section 9-1-1790 and who is otherwise eligible for service retirement may retire for purposes of this section without a break in service.